This invention relates to a method of manufacturing a semiconductor device, in particular, to an improved method of forming a contact hole.
Conventionally, in order to contact a metal film with a semiconductor substrate, an interlaid insulating layer is patterned so that a contact hole is formed. Thereafter, aluminium is deposited over the major surface of the structure, to form an aluminium film thereon. In the deposition step, aluminium is deposited on the exposed surface of the substrate through the contact hole. Next, the aluminium film is patterned so that an aluminium electrode or wiring contacting the substrate through the contact hole is formed.
However, with the prior art manufacturing method, some margin is required for the semiconductor substrate in forming the contact hole in order to compensate the displacement on masking at the lithography process. This lowers the packing density of elements formed in the semiconductor device.